Experimental analysis of textured falling film and membrane-based desorbers in a novel semi-open sorption-based humidity management system

Effective humidity management is a key challenge for engineering systems operating at extreme moisture contents such as building dehumidification and industrial drying. Conventional low-temperature condensation-based humidity management systems are energy-intensive because they couple dehumidification with sensible cooling. To address this, a thermally-driven, semi-open sorption-based humidity management system is developed, which separates latent and sensible loads by directly capturing moisture from the humid air. This approach eliminates the low-temperature cooling step, thereby allowing a high-temperature dehydration process with improved energy efficiency. The energy consumption of sorbent-based systems highly depends on the performance of their desorber modules. This study experimentally analyzes the performance of textured falling film and membrane-based desorbers in a semi-open sorption-based humidity management system. The effects of key operating parameters, including sorbent flow rate and desorber temperature, on drying performance are assessed at three representative air conditions with medium, high, and extreme humidity contents relevant to dehumidification in buildings and drying in industrial systems. The results showed that the moisture removal rate and drying energy efficiency increase at lower sorbent flow rates and higher desorber temperatures within the experimental range examined. More importantly, the membrane-based desorber module demonstrates a higher moisture removal rate and drying energy efficiency compared with its falling film desorber counterpart due to a reduction in associated heat and mass resistances. At a sorbent flow rate of 2.5 g/s and desorber temperature of 140 °C, the membrane-based desorber module showed a moisture removal rate of 2.5 g/m²-s and an energy efficiency of 63.7 %, which are 78.6 % and 64.2 % higher than the falling film desorber module, respectively. The findings obtained from this study expedite the development of advanced textured desorbers for next-generation semi-open liquid-desiccant humidity management systems for future energy-efficient buildings and industrial drying processes.